Mariner 40 hp 1987 Troubles - SOLVED!!!

[treasures]

Never had any issues with this motor before. We tried to do good by her and keep her spotless. Run the gas out of the engine after each trip. Anyways with that said, took the boat out a week ago, it was hard to start and finally got it going and had the boat on plane. The engine died after two miles and was hard to start again. It would only start with the warm up level up and would die out. We tried that often and finally it would not fire there after. Had to use electric to get back. Checked to see if water is pumping and it is. Checked plugs and we had spark and we checked the gap. Plugs were fouled - we cleaned them tightened back in. Checked diaphragm in fuel pump. Checked the fuel and the oil lines they are good. Checked compression and it is good. Pumped fuel bulb and it is squishy. You can hear a gurgle in the Carb area of the engine while pumping the bulb. There are two carbs. Oil and gas leaking from prop exhaust. Engine will not fire but turns over. Electric start, electric choke and oil injection.
Got a manual coming any day now and we are trying to figure out what went wrong. We want to tackle this job ourselves if we can. Any ideas on what I should check next?? Thanks for you time.

 

[CharlieB]

Re: Mariner 40 hp 1987 Troubles

Re: Mariner 40 hp 1987 Troubles

A squishy primer bulb and gurgling sounds from the carbs, usually meaning that the float is stuck or the needle is not seating, allowing one or more carbs to flood and foul the plugs.

It is time to clean the carbs.

 

[treasures]

Re: Mariner 40 hp 1987 Troubles

Re: Mariner 40 hp 1987 Troubles

Thanks Senior Chief ...got the Seloc this morning and I been reading!

 

[treasures]

Re: Mariner 40 hp 1987 Troubles

Re: Mariner 40 hp 1987 Troubles

Well, the answer turned out to be ... the gas pickup tube broke off at the inside top of the gas tank. So, the only thing pumping into the engine, via the bulb, was pure oil (and air) from the oil injection unit. After reading through the forum and considering what we read, then "CharlieB" mentioning carbs we thought something fuel related.

So we drained the oil tank and took the oil injection completely apart and made sure the filters and screens were clear. Reassembled the unit on the covered kitchen table (what, you never dissembled an oil injection unit in the kitchen?) and then filled it with fresh oil. Next we decided to remove the gas tank and use the fuel for the lawnmower (just in case it was bad). Right after that is when we saw the pickup tube in the bottom of the tank. It had been eaten/rotted inside the tank by the fuel over the years (alcohol) right where the clamp went around the tube at the top of the tank! After fixing that and getting new fuel we changed the plugs and turned the key for a second and the plugs instantly fouled with oil. We blew out all lines running to the engine and all lines leading to the carbs and then drained the carbs and filter of oil. Then we cleaned the plugs, pumped new fuel to the engine, turned the key, and it fired once. PROGRESS!

We cleaned the plugs again and same thing - plugs fouled with oil. This process of ?cleaning and drying? the plugs went on several more times and then FINALLY it fired and it was like a cloud from a nuclear bomb went off covering most of the house and all of the garage! GUNK blew out the exhaust onto the driveway. After about 15 seconds "she" idled right down and purred. Perfect! The smoke finally burned off from the excess oil and we then took the boat to the launch and just turned the key and it started right up. One more "hiccup/stall" after getting it up on plane and that was it. It's amazing now how smooth it is running. Idle is perfect, starting is perfect and acceleration is perfect. It sure feels good to have it up and running like this again and not having to take it in for troubleshooting at $100 an hour.

Now, thinking back over the last couple years, when it would act up just a little, it was probably the pickup tubing starting to break off and sucking some air into the line from the tank. Hope this helps someone else out in the future and Thanks for the great forum!